1. Field of the Invention
This invention relates to engine automatic start stop control apparatuses that automatically stop engines idling in accordance with prescribed conditions.
This application is based on Patent Application No. Hei 11-230132 filed in Japan, the content of which is incorporated herein by reference.
2. Description of the Related Art
Recently, people pay attention to environmental problems such as increasing temperature on the earth. So, automobile manufacturers and institutes are actively developing electric vehicles and hybrid vehicles to reduce discharges of gases and matters such as carbon dioxide. The electric vehicles are optimal solutions to the environmental problems because of zero discharge of gas. Under the present situation, however, the electric vehicles must be further developed to cope with technological disadvantages, as follows:
(i) The present electric vehicles are capable of running short distances with one-time electric charging.
(ii) The electric vehicles do not sufficiently catch up with capabilities and practical performance of the conventional vehicles using internal-combustion engines.
The hybrid vehicles are equipped with engines and motors, wherein batteries are charged in response to rotations of the engines. In prescribed low ranges of engine speeds where the engines produce relatively large amounts of carbon-dioxide discharges, the hybrid vehicles solely activate the motors or they activate both of the engines and motors in parallel, so it is possible to reduce amounts of carbon-dioxide discharges. The hybrid vehicles are practical solutions to the environmental problems because they are capable of reducing the carbon-dioxide discharges while securing performance (e.g., running distance and drivability) of the conventional vehicles. Recently, automobile manufacturers produce a variety of hybrid vehicles of practical use that are capable of running long distances by themselves.
In order to reduce amounts of discharges such as carbon dioxide and nitrogen oxide (NOx), engineers propose and develop an engine automatic stop start technique in which during a stop of a vehicle, an engine idling is stopped, then, the engine is started.
However, this technique is designed, regardless of an engine stall event, as follows:
In a hybrid vehicle, for example, when a driver makes an error operation to stop the vehicle under engagement of a clutch, an engine stall is caused to occur. In that case, the driver does not always recognize occurrence of the engine stall because of the error operation. In addition, the driver may mistakenly recognize that an idle stop control is made because the vehicle is stopped. In the event of the engine stall which is caused by the error operation of the driver, the engine is not stopped by the idle stop control. So, in order to normally restart the vehicle to run, the driver must operates a starter key to restart the engine running.
Since the driver mistakenly recognizes that the engine is stopped by the idle stop control, it is not expected for the driver to operate the starter key to restart the engine. Because the engine is stopped by the error operation of the driver, even if the driver drives the vehicle to start, the vehicle does not start from an idle stop state of the engine. In that case, acceleration may be differed from expected one at the start of the vehicle. So, the driver may have a feeling of wrongness because of xe2x80x9cunwantedxe2x80x9d acceleration. This causes a problem in that drivability is damaged.
It is an object of the invention to provide an engine automatic start stop control apparatus applicable to vehicles each of which is designed to perform idle stop control for reduction of discharge gas. Herein, the apparatus is capable of controlling restart operations of the vehicle without damaging drivability even if an engine of the vehicle stalls due to error operation of a driver.
This invention basically relates to an engine automatic start stop control apparatus that controls an engine to be automatically stopped and started in response to driving conditions of a vehicle.
According to a first aspect of the invention, the engine automatic start stop control apparatus comprises an engine speed detection device (18, SB12) for detecting engine speed of the engine, a clutch detection device (SB18) for detecting depression of a clutch pedal, an automatic stop detection device (18, SB10) for detecting an automatic stop mode of the engine, and an automatic start device (18, SB10-SB68) for automatically starting the engine if the clutch detection device detects the depression of the clutch pedal, the engine speed detection device detects that the engine speed is zero, and the automatic stop detection device does not detect the automatic stop mode of the engine.
In the above, the automatic start device controls the engine to restart based upon determination for restarting the engine under the engine stop mode. In addition, it controls the engine to restart if the driver depresses the clutch pedal although the engine stalls due to an error operation of the driver so that the engine speed becomes zero.
That is, the engine is restarted by operations for restarting the engine in the automatic stop mode even if the driver mistakenly recognizes that the engine is stopped by the automatic stop control although the engine stalls due to the error operation of the driver. Thus, it is possible to improve drivability for the driver who handles the vehicle.
According to a second aspect of the invention, the engine automatic start stop control apparatus comprises an engine speed detection device (18, SD12) for detecting engine speed of the engine, a brake detection device (SD22) for detecting depression of a brake pedal, an automatic stop detection device (18, SD10) for detecting an automatic stop mode of the engine, and an automatic start device (18, SD10-SD40) for automatically starting the engine if the brake detection device does not detect the depression of the brake pedal, the engine speed detection device detects that the engine speed is zero, and the automatic stop detection device does not detect the automatic stop mode of the engine.
In the above, the automatic start device controls the engine to restart if the driver depresses the brake pedal although the engine stalls due to the error operation of the driver so that the engine speed becomes zero.
According to a third aspect of the invention, the engine automatic start stop control apparatus is applicable to a hybrid vehicle that installs an electric motor (16) in addition to the engine (10) as driving sources of wheels.
Because the hybrid vehicle is capable of independently running by only using the electric motor, there is a great probability in that the driver fails to recognize the engine stall. The apparatus is capable of avoiding an unwanted situation where the battery coupled to the electric motor cannot be electrically charged for a long time because the engine stall continues.